# US 11,451,832 B2 · Signaling of chroma and luma syntax elements in video coding > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,451,832 B2 - Document ID: US11451832B2 - Status: Granted - Kind: B2 - Application number: 17/405,304 - Filed: 2021-08-18 - Published: 2021-12-09 - Granted: 2022-09-20 - Earliest claimed: 2019-04-20 - Assignees: Beijing Bytedance Network Technology Co., Ltd.; Bytedance Inc. - Applicants: Beijing Bytedance Network Technology Co., Ltd.; Bytedance Inc. - Inventors: Li Zhang; Kai Zhang; Hongbin Liu; Yue Wang - Web page: https://patentgrep.com/patent/US11451832B2 ## CPC - H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards - H04N 19/132: Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking - H04N 19/17: the unit being an image region, e.g. an object - H04N 19/176: the region being a block, e.g. a macroblock - H04N 19/186: the unit being a colour or a chrominance component - H04N 19/30: using hierarchical techniques, e.g. scalability (H04N19/63 takes precedence) - H04N 19/46: Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Devices, systems and methods related to management of syntax flags with respect chroma formats in video processing are described. In one representative aspect, a video decoding method includes determining, based on a chroma format of a video comprising a region, whether one or more syntax flags applicable to the region of the video are absent in a syntax structure of a coded representation of the video. The one or more syntax flags are indicative of usage of a luma-dependent chroma residue scaling coding step for representing the region in the coded representation. The luma-dependent chroma residue scaling coding step comprises a scaling process in which a scaling coefficient is derived based on reconstructed luma samples and the scaling process is applied to a chroma residue. The method also includes generating one or more decoded video blocks of the video region by parsing the coded representation according to the determining. ## Claims ### Claim 1 A method of processing video data, comprising: determining, based on a chroma format of a video comprising a region, whether one or more first syntax flags applicable to the region of the video are absent in a bitstream of the video, wherein the one or more syntax flags are indicative of usage of a first coding step for the region, wherein the first coding step is a chroma scaling process applied to a chroma residue in which a scaling coefficient is derived based on reconstructed luma samples; and performing a conversion between the region of the video and the bitstream based on a presence or an absence of the one or more first syntax flags, wherein the one or more first syntax flags are absent in the bitstream in case the chroma format is 4:0:0. ### Claim 2 (depends on 1) The method of claim 1, wherein the one or more first syntax flags are absent in the bitstream in case the chroma format is monochrome. ### Claim 3 (depends on 1) The method of claim 1, wherein the one or more first syntax flags are present in the bitstream in case the chroma format is not monochrome. ### Claim 4 (depends on 1) The method of claim 1, wherein the one or more first syntax flags are present in the bitstream in case the chroma format is not 4:0:0. ### Claim 5 (depends on 1) The method of claim 1, wherein the one or more first syntax flags are absent in the bitstream in case chroma components are coded separately. ### Claim 6 (depends on 1) The method of claim 1, wherein the one or more first syntax flags are present in the bitstream in case chroma components are not coded separately. ### Claim 7 (depends on 1) The method of claim 1, wherein in response to the chroma format being 4:0:0, the first coding step is not applied to the region of the video. ### Claim 8 (depends on 1) The method of claim 1, wherein the method further comprises determining, based on the chroma format of the region of the video, whether one or more second syntax flags applicable to the region of the video are included in the bitstream, wherein the one or more second syntax flags are indicative of a quantization parameter offset to a luma quantization parameter for the region, and wherein performing the conversion further based on a presence or an absence of the one or more second syntax flags. ### Claim 9 (depends on 8) The method of claim 8, wherein in response to the chroma format being 4:0:0, the one or more second syntax flags are not included in the bitstream. ### Claim 10 (depends on 1) The method of claim 1, wherein in response to the chroma format being 4:0:0, an adaptive loop filter is not applied to a chroma component of a first video unit of the region of the video. ### Claim 11 (depends on 1) The method of claim 1, wherein in response to the chroma format being 4:0:0, a secondary transform is not applied to a chroma component of a second video unit of the region of the video, and wherein the secondary transform is applicable between a forward primary transform and a quantization step or between a de-quantization step and an inverse primary transform. ### Claim 12 (depends on 11) The method of claim 11, wherein the secondary transform is a reduced secondary transform. ### Claim 13 (depends on 1) The method of claim 1, wherein in response to the chroma format being 4:0:0, a quantization scaling matrix is not applied to a chroma component of a third video unit of the region of the video. ### Claim 14 (depends on 1) The method of claim 1, wherein the region is a picture or a slice. ### Claim 15 (depends on 1) The method of claim 1, wherein the conversion includes encoding the video into the bitstream. ### Claim 16 (depends on 1) The method of claim 1, wherein the conversion includes decoding the video from the bitstream. ### Claim 17 An apparatus for processing video data comprising a processor and a non-transitory memory with instructions thereon, wherein the instructions upon execution by the processor, cause the processor to: determine, based on a chroma format of a video comprising a region, whether one or more first syntax flags applicable to the region of the video are absent in a bitstream of the video, wherein the one or more syntax flags are indicative of usage of a first coding step for the region, wherein the first coding step is a chroma scaling process applied to a chroma residue in which a scaling coefficient is derived based on reconstructed luma samples; and perform a conversion between the region of the video and the bitstream based on a presence or an absence of the one or more first syntax flags, wherein the one or more first syntax flags are absent in the bitstream in case the chroma format is 4:0:0. ### Claim 18 A non-transitory computer-readable storage medium storing instructions that cause a processor to: determine, based on a chroma format of a video comprising a region, whether one or more first syntax flags applicable to the region of the video are absent in a bitstream of the video, wherein the one or more syntax flags are indicative of usage of a first coding step for the region, wherein the first coding step is a chroma scaling process applied to a chroma residue in which a scaling coefficient is derived based on reconstructed luma samples; and perform a conversion between the region of the video and the bitstream based on a presence or an absence of the one or more first syntax flags, wherein the one or more first syntax flags are absent in the bitstream in case the chroma format is 4:0:0. ### Claim 19 A non-transitory computer-readable recording medium storing a bitstream of a video which is generated by a method performed by a video processing apparatus, wherein the method comprises: determining, based on a chroma format of a video comprising a region, whether one or more first syntax flags applicable to the region of the video are absent in a bitstream of the video, wherein the one or more syntax flags are indicative of usage of a first coding step for the region, wherein the first coding step is a chroma scaling process applied to a chroma residue in which a scaling coefficient is derived based on reconstructed luma samples; and generating the bitstream based on a presence or an absence of the one or more first syntax flags, wherein the one or more first syntax flags are absent in the bitstream in case the chroma format is 4:0:0. ### Claim 20 (depends on 17) The apparatus of claim 17, wherein the one or more first syntax flags are present in the bitstream in case the chroma format is not monochrome.